Hydrogenation of esters using alkali doped heterogeneous group VIII transition metal catalysts

Abstract

A novel class of heterogeneous catalysts, containing Group VIII transition metals in combination with alkali organic compounds is prepared, such as potassium naphthalene on ruthenium on carbon. The catalysts are useful as heterogeneous catalysts in the hydrogenation of carboxylic acid esters. A process for producing the materials is described. The catalysts permit the process of the hydrogenation of carboxylic acid esters to primary alcohols to be conducted with the ester in the liquid phase at a temperature not exceeding about 150° C. with high selectivity. Catalysts of Group VIII transition metals and alkali metal on carbon are also useful in such processes.

We claim: 
     
       1. A process for hydrogenating a monoester to the alcohols corresponding to the acid and alcohol portions of the monoester which comprises reacting hydrogen with the monoester in the liquid phase in the presence of solid catalyst composition at a temperature not exceeding about 150° C., said solid catalyst composition consisting essentially of about 0.1 to about 15 weight percent of at least one group VIII transition metal, about 1 to about 50 weight percent of at least one alkali metal cation, about 2 to about 50 weight percent of an anion radical selected from the group consisting of arene radical anions, ketyls, aliphatic alkoxide anions and mixtures thereof, and the balance of a support comprising high surface area carbon. 
     
     
       2. The process of claim 1 wherein the acid portion of the ester includes an aromatic ring. 
     
     
       3. The process of claim 1 or 14 or 15 wherein the acid portion of the ester is trifluoroacetyl. 
     
     
       4. The process of claim 3 wherein the ester is trifluoroethyl trifluoroacetate. 
     
     
       5. The process of claim 1 wherein the ester is in an inert solvent. 
     
     
       6. The process of claim 5 wherein the inert solvent is a polar ether. 
     
     
       7. The process of claim 6 wherein the inert solvent is tetrahydrofuran. 
     
     
       8. The process of claim 1 wherein the group VIII transition metal is ruthenium, rhodium, platinum or palladium. 
     
     
       9. The process of claim 1 wherein the radical anion is an arene radical anion selected from the group consisting of unsubstituted arene radical anions and arene radical anions substituted with alkyl, ether, dialkylamine or aryl. 
     
     
       10. The process of claim 9 wherein the arene radical anion is an unsubstituted arene radical anion. 
     
     
       11. The process of claim 9 wherein the arene radical anion is the naphthalene radical anion. 
     
     
       12. The process of claim 9 wherein the arene radical anion is the biphenyl radical anion. 
     
     
       13. The process of claim 9 wherein the arene radical anion is selected from the group consisting of the naphthalene, biphenyl, anthracene and phenanthrene radical anions. 
     
     
       14. The process of claim 1 wherein the radical anion is an aliphatic alkoxide radical anion. 
     
     
       15. The process of claim 14 wherein the aliphatic alkoxide anion has at most two carbons and is unsubstituted or substituted by fluorine only. 
     
     
       16. The process of claim 1 wherein the radical anion is a ketyl. 
     
     
       17. The process of claim 16 wherein the ketyl is diaryl ketyl. 
     
     
       18. The process of claim 16 wherein the ketyl is diphenyl ketyl. 
     
     
       19. The process of claim 1 wherein the alkali metal cation is about 2 to about 20 weight percent sodium or potassium cation or about 1 to about 5 weight percent lithium cation. 
     
     
       20. The process of claim 8 wherein the alkali metal cation is potassium cation. 
     
     
       21. A process for hydrogenating a monoester to the alcohols corresponding to the acid and alcohol portions of the monoester which comprises reacting hydrogen with the monoester in the liquid phase at a temperature not exceeding about 150° C. in the presence of a solid catalyst consisting essentially of about 0.1 to about 25 weight percent of at least one group VIII transition metal, about 0.5 to about 60 weight percent of at least one alkali metal and the balance an inert support comprising high surface area carbon. 
     
     
       22. The process of claim 21 wherein the group VIII transition metal is ruthenium, rhodium, platinum, or palladium. 
     
     
       23. The process of claim 22 wherein the group VIII transition metal is ruthenium. 
     
     
       24. The process of claim 22 wherein the group VIII transition metal is rhodium. 
     
     
       25. The process of claim 21 wherein the alkali metal is about 1 to about 5 weight percent lithium or about 2 to about 25 weight percent sodium or potassium. 
     
     
       26. The process of claim 25 wherein the alkali metal is potassium. 
     
     
       27. The process of claim 21 wherein the acid portion of the ester includes an aromatic ring. 
     
     
       28. The process of claim 21 wherein the acid portion of the ester is trifluoroacetyl. 
     
     
       29. The process of claim 28 wherein the ester is trifluoroethyl trifluoroacetate. 
     
     
       30. The process of claim 21 wherein the ester is in an inert solvent. 
     
     
       31. The process of claim 30 wherein the inert solvent is a polar ether. 
     
     
       32. The process of claim 31 wherein the inert solvent is tetrahydrofuran.